Rainbow Keys for Kids

I'm building a security system using Rainbow Signature encryption to ensure safe and secure handover of nursery school children. If a parent sends someone else to pick up their child, a dynamic one-time key will be generated for that specific event, which cannot be reused or predicted. Even if the key is leaked, it will be useless in future events. The child also won’t know the key in advance — instead, it will be calculated at runtime when the guardian is physically present. Although we're not using literal colors in the system, the mental model behind it is fully inspired by rainbow colors. These colors are easy for children to recognize and remember, and we're leveraging that concept creatively at a deeper, more advanced level to enhance the user experience and security. The rainbow theme acts as an intuitive and abstract base for our key mapping logic. This approach combines encryption, creativity, and child-friendly design to build a system that is both secure and easy to understand for everyone involved.

A smart mind, everyone can do this with little brainstorming

Define 6 rainbow colors: Red, Orange, Yellow, Green, Blue, and Purple.

(Indigo and Violet are combined into Purple for simplicity.)

These 6 colors are mapped to weekdays — Monday to Saturday.

Sunday is also mapped to Purple.

Each weekday is linked with one rainbow color.

For example:

1. Monday → Red
2. Tuesday → Orange
3. Wednesday → Yellow
4. Thursday → Green
5. Friday → Blue
6. Saturday/Sunday → Purple
7. Children will be taught this mapping, as it's easy to remember.

When a guardian comes to pick up a child, their T-shirt color will be used to generate a keyword.

Example: Red shirt → keyword = Apple or any red item

Before the pickup, the parent will share this KEY with the guardian — for example, "Banana leaf apple"

Parents may also ask the guardian in advance what color shirt they will be wearing, so the parent can generate KEY

Since both the day and clothing are likely to change next time, the same keyword cannot be reused. This keeps the system dynamic and secure.

The child’s own T-shirt color is also used to generate a second keyword.

Example: Purple shirt → keyword = Grapes or any purple item.

If the T-shirt color is not one of the six rainbow colors, the system will still work by using fallback mappings.

All other colors (like Black, White, Brown, etc.) will be predefined in a fallback list with their own mapped items.

Each pickup generates a dynamic key using 3 components:

1. The color of the current weekday
2. The guardian’s T-shirt color (mapped or fallback)
3. The child’s T-shirt color (mapped or fallback)

This system mixes creativity and security, no app, no typing.